The safety barricade industry is comprised of various types of companies that deal primarily in construction related signs and roadway markings. These safety barricades are temporary reflective signs that usually have one of two types of lights attached on the top. These lights are used as a guide to show roadway lane changes and merges during construction, or to mark a temporary obstruction such as a hole in the ground.
A standard structure commonly used in a barricade light includes a stand, a light housing mounted on the stand and a lens covering the light housing. If the lens is removed, the light housing may be viewed. The known light housing includes a tubular member reaching upwardly with a socket inside designed to receive an incandescent bulb. Various circuitry permits that incandescent bulb to function.
There are two types of markets in which a company in the industry may operate. There is the rental market, which is usually a major market for big projects. Additionally, the sales market must be considered for smaller projects.
The rental market involves companies that rent these barricades to be used on large state or federal projects, such as road or bridge construction. These projects may often require many barricades for use over a long period of time. These rental units are issued with a flat fee service contract for the rental company to maintain their operation at all times.
This maintenance requires having service vehicles to deliver, set-up and pick-up barricades at each job site. An additional maintenance requirement includes patrolling the job site and replacing any malfunctioning or damaged units as needed. This maintenance includes replacing batteries in the barricade lights when necessary.
The sales of barricade lights are usually made to those companies that have a need for safety lights, but are willing to provide their own maintenance and service when needed. These purchasers are usually smaller construction companies or utilities that may only require a few barricades at any given job site. Another sales area is to other rental companies, that do not manufacture barricades and lights of their own.
The barricade lights, currently being employed on an industry wide basis, are designed around the use of an incandescent bulb as the light source. There are two types of lighted barricades being used, a steady burn unit and a flasher unit. The steady burn unit is a constant illumination light that is only seen from one direction.
The other type of light is a flasher unit, which is seen from both directions and is flashing at a pre-designated flash rate set according to industry standards. The lens is mounted in such a way that allows it to be rotated 360 degrees without affecting the bulb, since the bulb is omni-directional. An electronic circuit is currently used to control voltage to the bulb and, in the case of the flashing unit, also sets the flash rate.
Both types of lights customarily are powered by two six-volt zinc lantern batteries. In both cases an incandescent bulb is mounted on top of a electric candle that rises up from the battery compartment.
Although the industry has used these types of lights for many years, these lights are not without their problems. The industry has an average attrition rate of about 40 percent, primarily due to theft, abuse or accident. It is because of this attrition that the industry has been driven to lower the cost of producing these lights in order to minimize revenue losses.
This cost requirement causes a further problem in that it has resulted in using some materials in construction that effect the usefulness of the lights while in the field. The general unreliability of the current incandescent light used in the barricade leads to excessive field failure and maintenance costs. These problems result in lower profit for the supplying company.
One of the main reasons for field failure of the lights is the basic nature of incandescent bulbs. The average life of an incandescent bulb used under proper conditions is only 400 hours and the bulbs tend to burn out at different and very unpredictable rates. Also, filaments of bulbs break very easily especially if the unit is jarred or dropped. This is a problem in the very rugged environment of the construction areas these lights are most used.
Another big area in which these lights fail is the low cost mechanical switch that is used to turn the units off when the lights are not being used. It is accurately estimated that over 80 percent of the barricade lights that are repaired are done so because the switch to turn the barricade light on or off is not working properly.
Corroded contacts in this switch sometimes make it impossible for the light to be turned on when needed. Protection of the switch can limit access for repair or use of the switch. It is desired to have the switch accessible, durable and inexpensive.
While a barricade light, may have a light activated switch while in use, it is desired to be able to turn the barricade light off for storage. A defective switch not only makes the barricade light difficult to turn off and store, it also wastes battery power.
A third problem area surrounds the batteries used in the barricade lights. In order to keep costs down standard zinc carbon six volt batteries are used. The typical useful life for these batteries in this application is approximately 250 hours use for a steady burn light and 1,000 hours for a flasher unit. This battery life is a major concern because of the great number of man hours used to simply replace dead batteries while the units are in the field.
A related problem for the battery surfaces when the issue of disposal of these batteries is brought into the fold. The safety barricade industry is the single largest user of these types of batteries, and uses millions are of those batteries each year. Certain local and state authorities are beginning to look closely at the environmental impact of battery disposal.
All of the above reasons lead to high maintenance costs needed to service these barricade lights properly and keep them in working condition. These costs increase when a barricade light is taken out of service to be repaired. Not only is that light unable to be a revenue producer but the costs for extra parts and labor to complete the repairs can add up quickly.
Thus it may be seen that there are many key problems facing the manufacturers and users of the barricade lights. These problems are sufficient to require an immediate solution, while maintaining the required low cost of the barricade light.
The solution to the existing problems with incandescent lights in the barricade industry is the use of Light Emitting Diode (LED) technology. By replacing the incandescent bulb with a LED the major problems can be easily addressed. However there is more to it than simply taking an incandescent bulb out and plugging in a LED.
The use of a light emitting diode to replace an incandescent bulb is not a new one. Many electrical and mechanical issues need to be addressed to accommodate the unique characteristics of LED'S combined with the existing regulations of the safety barricade industry.
Of the electrical issues to be addressed, the primary issues are circuit durability, switch durability, and battery life; all while maintaining the low cost. To achieve durability while maintaining low cost can provide a great advantage to the industry.
If the use of the light emitting diode can be achieved within the current structure of a barricade light, the substitution thereof for the incandescent bulb is greatly simplified. Substantial modification of the barricade light is not required.
A light emitting diode also increases battery life, due to less current being required to produce the appropriate light. It is also a more durable light, because there is no filament to break.